Stun guns are sold commercially for use in law enforcement, security applications, and self-defense. The principal behind stun gun application is basic. The body's electrical system is an efficient communication system where the brain instructs designated nerve cells to release a neurotransmitter, which is a communication chemical to muscle cells. At any given time, thousands of neurotransmitter signals are being sent throughout the body, and stun guns may disrupt this communication system. Stun guns generate a high-voltage, low-amperage electrical current. In simple terms, this means that the current has a significant pressure behind it, but not much intensity. When a stun gun is pressed against an attacker and the trigger is pressed, a charge passes into the attacker's body. Since it has a fairly high voltage the current will pass through heavy clothing and skin. At around 3 milliamps, the current is not intense enough to damage the attacker's body unless it is applied for extended periods of time. However, the delivered current results in a confusing amount of information on the attacker's nervous system. First the current combines with the electrical signals from the attacker's brain. Any original signal is mixed with what appears to be random noise, making it very difficult to decipher any messages. When these lines of communication are overwhelmed, the attacker has a very hard time instructing his muscles to move, and he may become confused and unbalanced.
The current may be generated with a pulse frequency that mimics the body's own electrical signals. In this case, the current will tell the attacker's muscles to do a great deal of work in a short amount of time. Since the work performed by the attacker's muscles during shock depletes the attacker's energy reserves, the attacker ideally becomes too weak to move.
There are varying models and techniques of stun weapons in use today. The three most popular devices, the handheld stun gun, the Taser type gun, and the liquid stun gun.
Stun-gun effectiveness varies depending on the particular gun model, the attacker's body size and his determination. Another factor is how long the gun is maintained in contact with the attacker and correspondingly, the length of time when shock is administered. If the gun is actuated for half a second, a painful jolt may startle the attacker. If the gun is applied and shock administered for one or two seconds, the attacker should experience muscle spasms and become dazed. If the attacker receives more than three seconds of shock, he will likely become unbalanced and disoriented and may lose muscle control. However, determined attackers with a certain physiology may keep coming despite any shock.
Conventional stun guns have a fairly simple design. They are about the size of a flashlight, and they work on ordinary batteries. The battery supplies electricity to a circuit consisting of various electrical components. The circuitry includes multiple transformers, components that boost the voltage in the circuit, typically to between 20,000 and 150,000 volts, and reduce the amperage. Conventional stun guns also include an oscillator, a component that fluctuates current to produce a specific pulse pattern of electricity. This current charges a capacitor. The capacitor builds up a charge, and releases it to the electrodes, the portion of the circuit where the shocking current is delivered to the attacker. The electrodes are often two plates of conducting metal positioned in the circuit with a gap between them. Since the electrodes are positioned along the circuit, they have a high voltage difference between them. If this gap is filled with a conductor (say, the attacker's body), the electrical pulses will try to move from one electrode the other, dumping electricity into the attacker's nervous system.
One popular variation on the conventional stun-gun design is the Taser-type gun. Taser-type guns work the same basic way as ordinary stun guns, except the two charge electrodes aren't permanently joined to the housing. Instead, they are positioned at the ends of long conductive wires, attached to the gun's electrical circuit. Pulling the trigger breaks open a compressed gas cartridge inside the gun. The expanding gas builds pressure behind the electrodes, launching them through the air, the attached wires trailing behind. The electrodes are affixed with small barbs so that they will grab onto an attacker's clothing or skin. When the electrodes are attached, the current travels down the wires into the attacker, providing a stunning effect in a similar manner as a conventional stun gun.
The main advantage of the Taser-type design is that attackers can be stunned from a greater distance (typically 15 to 20 feet/4 to 6 meters). One disadvantage is that the person using the gun only gets one shot to make contact. One must wind up and re-pack the electrode wires, as well as load a new gas cartridge, each time the device is fired. Most models also have conventional stun-gun electrodes, in case the flying electrodes miss the target.
One of the newer stun weapons is the liquid stun gun. These devices work the in a similar manner to Taser-type guns except they use a liquid stream to conduct electricity rather than extended wires. The liquid stun gun is connected to a tank of highly conductive liquid, typically a mixture of water, salt and various other conductive elements. When the trigger is pulled, electrical current travels from the gun, through the liquid stream, to the attacker. These guns have a longer firing range than Taser-type guns, and can be shot many times in succession. They are generally more cumbersome than Taser-type guns, however, because of the need to store, transport, and emit conductive liquid. High-powered guns work with vehicle-mounted water cannons, while portable models typically include a water tank backpack.
Most current stun-gun models have two pairs of electrodes: an inner pair and an outer pair. The outer pair of electrodes is spaced a distance apart, so current will only flow if an outside conductor, such as an attacker's body part, is inserted. If the current cannot flow across these electrodes, it flows to the inner pair of test electrodes. These electrodes are close enough that the electric current can leap between them through an air gap. The moving current ionizes the air particles in the gap, producing a visible spark and crackling noise. This display is mainly intended as a deterrent. An attacker sees and hears the electricity and knows that the person holding the stun gun is capable of administering a shock. Some stun guns rely on the element of surprise, rather than producing a warning. These models are disguised as umbrellas, flashlights or other everyday objects that may catch attackers off guard.
Handcuffs are more traditionally used by law enforcement, and security forces. Handcuffs are restraining devices designed to secure an individual's wrists close together. They comprise two halves, linked together by a chain, hinge or in the case of rigid cuffs, a bar. Each half has a rotating part which engages with a ratchet which is closed around a person's wrist. Without the key, the person cannot move their wrists more than a few centimeters/inches apart, making many tasks difficult or impossible. This is usually done to prevent suspected criminals from escaping police custody. There are two distinct subtypes of contemporary metal handcuffs: one in which the cuffs are held together by a short chain, and another, of more recent origin, which uses a hinge for this purpose. Since the hinged handcuffs are somewhat smaller when fully extended they are seen as being more easily utilized by a police officer who has relatively small hands, and are also regarded by some observers as more secure because the wrists end up being held closer together than with the chain subtype, and are also bound more rigidly. A third type, the rigid handcuff, has a metal block or bar between the cuffs. While bulkier to carry, it permits several variations in cuffing. An example of rigid handcuffs is Hiatts Speedcuffs as used by most police forces in the United Kingdom. Both rigid and hinged cuffs can be used one-handed to apply pain-compliance/control techniques that are not workable with the chain type of cuff. Various accessories are available to improve the security or increase the rigidity of handcuffs, including boxes that fit over the chain or hinge and can themselves be locked with a padlock.
Handcuffs with double locks have a lock-spring that when engaged stops the cuff from ratcheting tighter to prevent the wearer from tightening them. Tightening could be intentional or by struggling, when tightened the handcuffs may cause nerve damage or loss of circulation. Also, some wearers could tighten the cuffs to attempt an escape by having the officer loosen the cuffs and while the cuffs are loose attempt the escape. Double locks also make picking the locks more difficult.
Three kinds of double locks for handcuffs include the lever lock, the push pin lock, and the slot lock. The lever lock is double-locked by fully lifting the lever with a fingertip and then allowing it to return. This causes the lock spring to move into a position that locks the bolt thus preventing the cuff from being further tightened. Thus no tool is required to double lock of this kind. The push pin lock is double-locked by fully depressing the push pin using the small peg on the top of the key. This causes the lock spring to move into a position that locks the bolt thus preventing the cuff from being further tightened. The slot lock is double-locked by inserting the small peg on the top of the key into the double lock slot. In this position, the small peg can contact the end of the lock spring. The key is then slid towards the key hole. This causes the lock spring to move into a position that locks the bolt, thus preventing the cuff from being further tightened.
On occasions when a suspect exhibits extremely aggressive behavior, leg irons may be used as well; sometimes the chain connecting the leg irons to one another is looped around the chain of the handcuffs, and then the leg irons are applied, resulting in the person being “hog-tied”. In a few rare cases, hog-tied persons lying on their stomachs have died from positional asphyxia, making the practice highly controversial, and leading to its being severely restricted, or even completely banned, in many localities. However, when a person is restrained within handcuffs and/or leg irons there are many reports of these individuals escaping and/or causing serious injuries to law enforcement personnel. Thus, a need exists for a device, which overcomes these and other restraint and separate electric shock device problems.